Pressure-sensitive adhesive composition, pressure-sensitive adhesive film, and method of manufacturing organic electronic device using the same

ABSTRACT

Provided are a pressure-sensitive adhesive composition, a pressure-sensitive adhesive film, and a method of manufacturing an organic electronic device using the same. The pressure-sensitive adhesive composition that may effectively block moisture or oxygen penetrated into an organic electronic device from an external environment, and exhibit reliability under harsh conditions such as high temperature and high humidity and excellent optical characteristics, and a pressure-sensitive adhesive film including the same are provided.

This application is a Continuation Application of U.S. patentapplication Ser. No. 14/765,482 filed on Aug. 3, 2015, now allowed,which is a National Stage Entry of International Application No.PCT/KR2014/007236, filed Aug. 5, 2014, and claims the benefit of KoreanApplication No. 10-2013-0092782, filed on Aug. 5, 2013, and KoreanApplication No. 10-2014-0040827, filed Apr. 4, 2014, all of which arehereby incorporated by reference in their entirety for all purposes asif fully set forth herein.

BACKGROUND 1. Field of the Invention

The present invention relates to a pressure-sensitive adhesivecomposition, a pressure-sensitive adhesive film, and a method ofmanufacturing an organic electronic device using the same.

2. Discussion of Related Art

An organic electronic device (OED) refers to a device including anorganic material layer generating alternation of charges using holes andelectrons, and may include, for example, a photovoltaic device, arectifier, a transmitter, and an organic light emitting diode (OLED).

A representative OED, which is an OLED, has less power consumption and ahigher response speed, and forms a thinner display device or light thana conventional light source. In addition, the OLED has excellent spaceutilization, and is expected to be applied in various fields includingall kinds of portable devices, monitors, notebook computers, and TVs.

To extend commercialization and use of the OLED, a major problem isdurability. Organic materials and metal electrodes included in the OLEDare very easily oxidized by external factors such as water. Accordingly,a product including the OLED is very sensitive to environmental factors.Therefore, various methods for preventing penetration of oxygen or waterfrom an external environment with respect to an organic electronicdevice such as the OLED have been suggested.

In Korean Unexamined Patent No. 2008-0088606, an adhesive capsulatedcomposition and an organic electroluminescence light emitting device areprovided, and have poor processability as a pressure-sensitive adhesivebased on polyisobutylene (PIB), and low reliability at high temperatureand high humidity.

Accordingly, in an organic electronic device, it is required to developan encapsulant ensuring a required life span, excellently preventingpenetration of moisture, maintaining reliability at high temperature andhigh humidity, and having excellent optical characteristics.

SUMMARY OF THE INVENTION

The present invention is directed to providing a pressure-sensitiveadhesive composition which can form a structure effectively preventingmoisture or oxygen penetrated into an organic electronic device from anexternal environment, and has excellent mechanical characteristics suchas handleability and processability and excellent transparency, apressure-sensitive adhesive film, and a method of manufacturing anorganic electronic device using the same.

In one aspect, the present invention provides a pressure-sensitiveadhesive composition. The pressure-sensitive adhesive composition may beapplied to, for example, encapsulation or capsulation of an organicelectronic device such as an OLED.

The term “organic electronic device” used herein refers to a product ordevice having a structure including an organic material layer generatingalternation of charges using holes and electrons between a pair ofelectrodes facing each other, and may include, but is not limited to,for example, a photovoltaic device, a rectifier, a transmitter, and anorganic light emitting diode (OLED). In one example, the organicelectronic device may be an OLED.

The pressure-sensitive adhesive composition of the present invention mayhave a gel content represented by Equation 1 of 50% or more, and a microgel content represented by Equation 2 of 3% or less.Gel content (wt %)=B/A×100  [Equation 1]Micro gel content (wt %)=C/A×100  [Equation 2]

In Equation 1, A is a mass of the pressure-sensitive adhesivecomposition, and B is a dry mass of an insoluble content of thepressure-sensitive adhesive composition remaining after being dipped intoluene at 60° C. for 24 hours and filtered through a 200-mesh sieve(pore size of 200 μm).

Also in Equation 2, A is a mass of the pressure-sensitive adhesivecomposition, and C is a dry mass of an insoluble content of thepressure-sensitive adhesive composition remaining after being dipped intoluene at 60° C. for 24 hours, primarily filtered through a 200-meshsieve (pore size: 200 μm), and secondarily filtered through a 1000-meshsieve (pore size: 5 μm).

The gel content represented by Equation 1 may be 50 to 99%, 50 to 90%,50 to 80%, or 50 to 70%. In addition, the micro gel content representedby Equation 2 may be 3%, 2%, 1%, 0.8%, or 0.5% or less. Here, the lowerlimit is not particularly limited, and may be 0%. When the micro gelcontent is 0%, the pressure-sensitive adhesive composition maysecondarily be filtered through a 1000-mesh sieve (pore size: 5 μm), anda dry mass of the pressure-sensitive adhesive composition remainingafter filtering may be 0. In addition, the micro gel may be identifiedusing a syringe having a size of 5 μm. For example, when thepressure-sensitive adhesive composition is primarily filtered through a200-mesh sieve (pore size: 200 μm) and the filtered solution passesusing a syringe having a size of 5 μm, the syringe is clogged with amicro gel (having a size of approximately 100 nm to 20 μm) present in acomposition having a micro gel content represented by Equation 2 of morethan 3%, and therefore the composition does not pass. On the other hand,when almost no or no micro gel is present in the crosslinking structure,the composition passes through the syringe, and has a micro gel contentof within 3% (actually, close to almost 0%) represented by Equation 2.In addition, the presence of an actual micro gel may be confirmedthrough morphological analysis. The micro gel observed through themorphological analysis may have a size of approximately 100 nm to 20 μm.The syringe may be any one that has a size of 5 μm without particularlimitation, and thus may be a micro filter generally used in the art.

That is, the micro gel content represented by Equation 2 is a value withrespect to a sol component that does not pass through or remaining afterthe pressure-sensitive adhesive composition is dipped in toluene at 60°C. for 24 hours and filtered through a 1000-mesh sieve (pore size: 5μm), which may determine the presence of a micro gel in thepressure-sensitive adhesive composition, and therefore becoming anindicator that can realize desired reliability and opticalcharacteristics. That is, it is not enough to determine a crosslinkingstructure and a degree of crosslinking only with the conventional gelcontent, and thus suitable ranges of the crosslinking structure anddegree of crosslinking of a pressure-sensitive adhesive composition aredetermined using a micro gel content, thereby realizing apressure-sensitive adhesive composition having excellent moisturebarrier ability, reliability, and optical characteristic.

The pressure-sensitive adhesive composition may have a water vaportransmission rate (WVTR) measured in a thickness direction of the filmwhile being formed in a film having a thickness of 100 μm of 50, 40, 30,20, or 10 g/m²·day or less at 100° F. and a relative humidity of 100%.By controlling a composition or crosslinking condition of apressure-sensitive adhesive composition to have such a WVTR, anencapsulation or capsulation structure which can stably protect anelement by effectively blocking moisture or oxygen penetrated from anexternal environment when being applied to an encapsulation orcapsulation structure of an electronic device may be realized. The lowerWVTR, the better moisture barrier ability, and therefore the lower limitof the WVTR may be, but is not particularly limited to, 0 g/m²·day.

In addition, the pressure-sensitive adhesive composition may have anexcellent light transmittance with respect to a visible-ray region. Inone example, the pressure-sensitive adhesive composition of the presentinvention is formed in a film and may have a light transmittance of 85%or more with respect to the visible-ray region. For example, thepressure-sensitive adhesive composition is formed in a film and may havea light transmittance of 85%, 87%, or 90% or more with respect to thevisible-ray region. In addition, the pressure-sensitive adhesivecomposition of the present invention may have a low haze with theexcellent light transmittance. In one example, the pressure-sensitiveadhesive composition may be formed in a film and have a haze of 3%, 2%,1%, 0.8%, 0.5%, or 0.3% or less. That is, the pressure-sensitiveadhesive composition of the present invention may realize excellentoptical characteristics as well as reliability at high temperature andhigh humidity by satisfying the gel content and micro gel contentaccording to Equations 1 and 2 as described above.

The pressure-sensitive adhesive composition of the present invention maybe formed using known various materials as long as satisfying thephysical properties.

For example, the pressure-sensitive adhesive composition may include anencapsulating resin and a multifunctional active energyray-polymerizable compound that can be polymerized by irradiation of anactive energy ray.

In an exemplary embodiment of the present invention, the encapsulatingresin may have a glass transition temperature of less than 0, −10, −30,−50, or −60° C. Here, the glass transition temperature may refer to aglass transition temperature after a UV ray is irradiated at a dose ofapproximately 1 J/cm² or more, or a glass transition temperature afterthermal curing is additionally performed after UV irradiation.

In one example, the encapsulating resin may include a styrene-basedresin or an elastomer, a polyolefin-based resin or an elastomer, otherelastomers, a polyoxyalkylene-based resin or an elastomer, apolyester-based resin or an elastomer, a polyvinylchloride-based resinor an elastomer, a polycarbonate-based resin or an elastomer, apolyphenylenesulfide-based resin or an elastomer, a mixture ofhydrocarbon, a polyamide-based resin or an elastomer, an acrylate-basedresin or an elastomer, an epoxy-based resin or an elastomer, asilicon-based resin or an elastomer, a fluorine-based resin or anelastomer, or a mixture thereof.

Here, the styrene-based resin or an elastomer may be, for example, astyrene-ethylene-butadiene-styrene (SEBS) block copolymer, astyrene-isoprene-styrene (SIS) block copolymer, anacrylonitrile-butadiene-styrene (ABS) block copolymer, anacrylonitrile-styrene-acrylate (ASA) block copolymer, astyrene-butadiene-styrene (SBS) block copolymer, a styrene-basedhomopolymer, or a mixture thereof. The olefin-based resin or anelastomer may be, for example, a high density polyethylene-based resinor an elastomer, a low density polyethylene-based resin or an elastomer,a polypropylene-based resin or an elastomer, or a mixture thereof. Theelastomer may be, for example, an ester-based thermoplastic elastomer,an olefin-based elastomer, a silicon-based elastomer, an acrylicelastomer, or a mixture thereof. Among these, the olefin-basedthermoplastic elastomer may be a polybutadiene resin or an elastomer ora polyisobutylene resin or an elastomer. The polyoxyalkylene-based resinor an elastomer may be, for example, a polyoxymethylene-based resin oran elastomer, a polyoxyethylene-based resin or an elastomer, or amixture thereof. The polyester-based resin or an elastomer may be, forexample, a polyethylene terephthalate-based resin or an elastomer, apolybutylene terephthalate-based resin or an elastomer, or a mixturethereof. The polyvinylchloride-based resin or an elastomer may be, forexample, polyvinylidene chloride. The mixture of hydrocarbon may be, forexample, hexatriacontane or paraffin. The polyamide-based resin or anelastomer may be, for example, nylon. The acrylate-based resin or anelastomer may be, for example, polybutyl(meth)acrylate. The epoxy-basedresin or an elastomer may be, for example, a bisphenol-type such as abisphenol A-type, a bisphenol F-type, a bisphenol S-type, and ahydrogenated product thereof; a novolac-type such as aphenolnovolac-type or a cresolnovolac-type; a nitrogen-containingring-type such as a triglycidylisocyanurate-type or a hydantoin-type; analicyclic-type; an aliphatic-type; an aromatic-type such as anaphthalene-type or a biphenyl-type; a glycidyl-type such as aglycidylether-type, a glycidylamine-type, or a glycidylester-type; adicyclo-type such as a dicyclopentadiene-type; an ester-type; anetherester-type; or a mixture thereof. The silicon-based resin or anelastomer may be, for example, polydimethylsiloxane. In addition, thefluorine-based resin or an elastomer may be a polytrifluoroethyleneresin or an elastomer, a polytetrafluoroethylene resin or an elastomer,a polychlorotrifluoroethylene resin or an elastomer, apolyhexafluoropropylene resin or an elastomer, polyvinylidene fluoride,polyvinyl fluoride, polyethylenepropylene fluoride, or a mixturethereof.

The above-listed resins or elastomers may be grafted to, for example,maleic anhydride, copolymerized with another one of the listed resins orelastomers or a monomer for preparing the resin or elastomer, ormodified by a compound, other than the above-used resins or elastomers.The compound may be a carboxyl-terminated butadiene-acrylonitrilecopolymer.

In one example, the pressure-sensitive adhesive composition is anencapsulating resin, which may include an olefin-based elastomer, asilicon-based elastomer, or an acrylic elastomer of the above-describedtypes, but the present invention is not limited thereto.

Specifically, the encapsulating resin may be a copolymer of a diene andan olefin-based compound having one carbon-carbon double bond. Here, theolefin-based compound may include isobutylene, propylene, or ethylene,and the diene may be a monomer capable of being polymerized with theolefin-based compound, for example, 1-butene, 2-butene, isoprene, orbutadiene. That is, the encapsulating resin of the present invention maybe, for example, a homopolymer of an isobutylene monomer; a copolymerprepared by copolymerizing an isobutylene monomer with a monomer capableof being polymerized therewith; or a mixture thereof. In one example,the copolymer of the diene and the olefin-based compound having onecarbon-carbon double bond may be a butyl rubber. When a specific resinis used as described above, moisture barrier ability that would beachieved in the present invention may be satisfied. In addition, thepresent invention may improve humidity resistance and heat resistance byintroducing various crosslinking structures and realizing specific gelcontent and micro gel content since a conventional isobutylene polymerhas a low moisture permeability but has low heat resistance.

In the pressure-sensitive adhesive composition, the resin or elastomercomponent may have a weight average molecular weight (Mw) to an extentthat the pressure-sensitive adhesive composition can be plasticized in afilm type. For example, the resin or elastomer may have a weight averagemolecular weight (Mw) of approximately 100,000 to 2,000,000, 100,000 to1,500,000, or 100,000 to 1,000,000. The term “weight average molecularweight” used herein refers to a converted value with respect to standardpolystyrene measured by gel penetration chromatography (GPC). However,the resin or elastomer component does not necessarily have theabove-mentioned weight average molecular weight. For example, when amolecular weight of the resin or elastomer component is not sufficientfor forming a film, a separate binder resin may be blended in thepressure-sensitive adhesive composition.

The pressure-sensitive adhesive composition of the present invention mayinclude, as described above, an active energy ray-polymerizable compoundhaving high compatibility with the encapsulating resin and capable offorming a specific crosslinking structure with the encapsulating resin.In one exemplary embodiment, the crosslinking structure may be acrosslinking structure formed by application of heat, a crosslinkingstructure formed by irradiation of an active energy ray, or acrosslinking structure formed by aging at room temperature. Here, in thecategory of the “active energy ray”, a microwave, an infrared (IR) ray,an ultraviolet (UV) ray, an X ray, and a gamma ray, and a particle beamsuch as an alpha-particle beam, a proton beam, a neutron beam, or anelectron beam, and conventionally, an UV ray or an electron beam may beincluded.

For example, the pressure-sensitive adhesive composition of the presentinvention may include a multifunctional active energy ray-polymerizablecompound that can be polymerized by irradiation of an active energy raywith the encapsulating resin. The active energy ray-polymerizablecompound may refer to, for example, a compound including at least two offunctional groups that can participate in a polymerization reaction byirradiation of an active energy ray, for example, a functional groupincluding an ethylene-like unsaturated double bond such as an acryloylgroup or a methacryloyl group, and a functional group such as an epoxygroup or an oxetane group.

As the multifunctional active energy ray-polymerizable compound, forexample, a multifunctional acrylate (MFA) may be used.

In addition, the multifunctional active energy ray-polymerizablecompound that can be polymerized by the irradiation of an active energyray may satisfy Formula 1. In addition, the active energyray-polymerizable compound may be included at 5 to 30, 5 to 25, 8 to 20,10 to 18, or 12 to 18 parts by weight relative to 100 parts by weight ofthe encapsulating resin.

In Formula 1, R₁ is hydrogen or an alkyl group having 1 to 4 carbonatoms, n is an integer of 2 or more, and X is a residue induced from alinear, branched, or cyclic alkyl group having 3 to 30 carbon atoms.Here, when X is a residue induced from a cyclic alkyl group, X may be,for example, a residue induced from a cyclic alkyl group having 3 to 30,6 to 28, 8 to 22, or 12 to 20 carbon atoms. In addition, when X is aresidue induced from a linear alkyl group, X may be a residue inducedfrom a linear alkyl group having 3 to 30, 6 to 25, or 8 to 20 carbonatoms. In addition, when X is a residue induced from a branched alkylgroup, X may be a residue induced from a branched alkyl group having 3to 30, 5 to 25, or 6 to 20 carbon atoms.

The term “residue induced from an alkyl group” used herein may refer toa residue of a specific compound composed of an alkyl group. In oneexample, in Formula 1, when n is 2, X may be an alkylene group. Inaddition, when n is 3 or more, at least two hydrogens of the alkyl groupmay be released from X, and then bind to a (meth)acryloyl group ofFormula 1.

The term “alkyl group” used herein may refer to, but is not particularlydefined otherwise, an alkyl group having 1 to 30, 1 to 25, 1 to 20, 1 to16, 1 to 12, 1 to 8, or 1 to 4 carbon atoms. The alkyl group may have alinear, branched, or cyclic structure, and may be optionally substitutedby at least one substituent.

The term “alkylene group” used herein may be, but is not particularlydefined otherwise, an alkylene group having 2 to 30, 2 to 25, 2 to 20, 2to 16, 2 to 12, 2 to 10, or 2 to 8 carbon atoms. The alkylene group mayhave a linear, branched, or cyclic structure, and may be optionallysubstituted by at least one substituent.

The multifunctional active energy ray-polymerizable compound that can bepolymerized by the irradiation of an active energy ray may be any onesatisfying Formula 1 without limitation. For example, the compound maybe 1,4-butanediol di(meth)acrylate, 1,3-butylene glycoldi(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,8-octanedioldi(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, neopentylglycoldi(meth)acrylate, dicyclopentanyl di(meth)acrylate,cyclohexane-1,4-dimethanol di(meth)acrylate, tricyclodecanedimethanol(meth)diacrylate, dimethylol dicyclopentane di(meth)acrylate, neopentylglycol modified trimethylpropane di(meth)acrylate, adamantanedi(meth)acrylate, trimethylolpropane tri(meth)acrylate, or a mixturethereof.

As the multifunctional active energy ray-polymerizable compound, forexample, a compound having a molecular weight of less than 1,000 andincluding at least two functional groups may be used. In this case, themolecular weight may refer to a weight average molecular weight or aconventional molecular weight. A cyclic structure included in themultifunctional active energy ray-polymerizable compound may be any oneof a carbocyclic structure, a heterocyclic structure, a monocyclicstructure, and a polycyclic structure.

In one exemplary embodiment of the present invention, thepressure-sensitive adhesive composition may include a silane compoundsatisfying Formula 2:

In Formula 2, R₁ is hydrogen or an alkyl group. R₁ may be, for example,an alkyl group having 1 to 4 or 1 to 2 carbon atoms. In addition, inFormula 2, R₂ and R₃ are each independently hydrogen, or a linear,branched, or cyclic alkyl group, or R₂ is linked with R₃, therebyforming a cyclic alkyl group. For example, R₂ and R₃ may be eachindependently hydrogen, or a linear, branched, or cyclic alkyl group.Here, the linear alkyl group may have 1 to 10, 1 to 6, or 1 to 4 carbonatoms, the branched alkyl group may have 3 to 10, 3 to 6, or 3 to 4carbon atoms, and the cyclic alkyl group may have 3 to 10, 3 to 8, 3 to6, or 3 to 4 carbon atoms. In addition, R₂ may be linked with R₃,thereby forming a cyclic alkyl group having 2 to 10, 3 to 10, 4 to 9, or4 to 8 carbon atoms. In addition, in Formula 2, R₄, R₅, and R₆ are eachindependently hydrogen, an alkyl group, or an alkoxy group, at least oneof R₄, R₅, and R₆ is an alkoxy group, and n is an integer of 1 or more.Particularly, R₄, R₅, and R₆ are each independently an alkyl grouphaving 1 to 10, 1 to 6, 1 to 4, or 1 to 2 carbon atoms; or an alkoxygroup having 1 to 10, 1 to 8, 1 to 4, or 1 to 2 carbon atoms. Here, atleast one of R₄, R₅, and R₆ may be an alkoxy group, and all of R₄, R₅,and R₆ may be alkoxy groups, but the present invention is not limitedthereto.

The term “alkoxy group” used herein may be, unless particularly definedotherwise, an alkoxy group having 1 to 20, 1 to 16, 1 to 12, 1 to 8, or1 to 4 carbon atoms. The alkoxy group may be a linear, branched, orcyclic type. In addition, the alkoxy group may be optionally substitutedby at least one substituent.

In one example, the silane compound is not particularly limited, as longas it satisfies Formula 2, and may be, for example, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxy propyl triethoxysilane, 3-acryloxypropyl trimethoxysilane, 3-acryloxy propyl triethoxysilane,3-methacryloxy methyl triethoxysilane, 3-methacryloxy methyltrimethoxysilane, 3-acryloxy propyl methyldimethoxysilane, methacryloxymethyl methyldimethoxysilane, methacryloxy methyl methyldiethoxysilane,methacryloxy propyl methyldimethoxysilane, methacryloxy propylmethyldiethoxysilane, methacryloxy propyl dimethylmethoxysilane, ormethacryloxy propyl dimethylethoxysilane. An acryl group of the silanecompound may serve to increase an interface pressure-sensitive adhesivestrength by being crosslinked with the encapsulating resin or activeenergy ray-polymerizable compound of the pressure-sensitive adhesivecomposition. The silane compound may be included at, for example, 0.1 to10, 0.5 to 8, 0.8 to 5, 1 to 5, 1 to 4.5, or 1 to 4 parts by weightrelative to 100 parts by weight of the encapsulating resin.

In one example, the active energy ray-polymerizable compound may form acrosslinking structure with the silane compound satisfying Formula 2,and the crosslinking structure may form a semi-interpenetrating polymernetwork (semi-IPN) with the encapsulating resin. That is, thepressure-sensitive adhesive composition may include a semi-IPN. The term“semi-IPN” includes at least one polymer crosslinking structure (polymernetwork) and at least one linear or branched polymer, and at least apart of the linear or branched polymer has a structure penetrated intothe polymer crosslinking structure. The semi-IPN may be distinguishedfrom an IPN structure in that the linear or branched polymer can betheoretically separated from the polymer crosslinking structure withoutloss of a chemical bond.

In one exemplary embodiment, the crosslinking structure may be acrosslinking structure formed by application of heat, a crosslinkingstructure formed by irradiation of an active energy ray, or acrosslinking structure formed by aging at room temperature. Here, in thecategory of the “active energy ray”, a microwave, an infrared (IR) ray,an ultraviolet (UV) ray, an X ray, and a gamma ray, and a particle beamsuch as an alpha-particle beam, a proton beam, a neutron beam, or anelectron beam, and conventionally, an UV ray and an electron beam may beincluded. As such a semi-IPN structure is introduced, a mechanicalproperty such as processability of the pressure-sensitive adhesivecomposition may be increased, humidity-resistant adhesive performance isimproved, transparency is realized, and high moisture barrierperformance and an excellent panel life span that cannot be achieved sofar may be realized.

In one example, the active energy ray-polymerizable compound may form acrosslinking structure with the silane compound satisfying Formula 2,and the encapsulating resin may form a crosslinking structure with theactive energy ray-polymerizable compound or the silane compoundsatisfying Formula 2, thereby forming an interpenetrating polymernetwork (IPN) structure. In addition, the term “IPN structure” refers toa state in which at least two crosslinking structures are present in apressure-sensitive adhesive. In one example, the IPN structure may referto a structure including at least two crosslinking structures in anintertwining, entanglement, or penetrating state. For example, thecomposition of the present invention may include a crosslinkingstructure by an encapsulating resin (hereinafter, referred to as a“first crosslinking structure”) and a crosslinking structure formed by areaction of an active energy ray-polymerizable compound and the silanecompound satisfying Formula 2 (hereinafter, referred to as a “secondcrosslinking structure”), and the first and second crosslinkingstructures may be in a penetrating state or an entanglement state. Thatis, as the pressure-sensitive adhesive composition includes a semi-IPNor IPN structure in a crosslinked state, excellent durability andreliability of a pressure-sensitive adhesive may be realized under harshconditions such as high temperature and high humidity by increasing apressure-sensitive adhesive strength of a pressure-sensitive adhesive athigh temperature and high humidity and preventing a decrease in aninterface pressure-sensitive adhesive strength due to moisturepenetration.

In an exemplary embodiment of the present invention, thepressure-sensitive adhesive composition may further include a radicalinitiator that can induce a polymerization reaction of theabove-described active energy ray-polymerizable compound. The radicalinitiator may be a photoinitiator or a thermal initiator. A specifictype of the photoinitiator may be suitably selected in consideration ofa curing rate and possibility of yellowing. For example, as thephotoinitiator, a benzoin-, hydroxy ketone-, amino ketone-, or phosphineoxide-based photoinitiator, and specifically, benzoin, benzoinmethylether, benzoin ethylether, benzoin isopropylether, benzoinn-butylether, benzoin isobutylether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone,2,2-diethoxy-2-phenylacetophenone,2-hydroxy-2-methyl-1-phenylpropane-1-one,1-hydroxycyclohexylphenylketone,2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propane-1-one,4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone,p-phenylbenzophenone, 4,4′-diethylaminobenzophenone,dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone,2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone,2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone,2,4-diethylthioxanthone, benzyldimethylketal, acetophenonedimethylketal, p-dimethylamino benzoic acid ester,oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone], or2,4,6-trimethylbenzoyl-diphenyl-phosphineoxide may be used.

The radical initiator may be included at 0.2 to 20 parts by weightrelative to 100 parts by weight of the active energy ray-polymerizablecompound. Accordingly, the reaction of the active energyray-polymerizable compound is effectively induced, and degradation ofphysical properties of the pressure-sensitive adhesive composition dueto remaining components after curing may be prevented.

In one example, the pressure-sensitive adhesive composition may furtherinclude a tackifier. The tackifier may be a hydrogenated annularolefin-based polymer. As the tackifier, for example, a hydrogenatedpetroleum resin obtained by hydrogenating a petroleum resin may be used.The hydrogenated petroleum resin may be partially or completelyhydrogenated, and may be a mixture of such resins. Such a tackifier mayhave a high compatibility with the pressure-sensitive adhesivecomposition, excellent moisture barrier ability, and a small content ofan organic volatile component. A specific example of the hydrogenatedpetroleum resin may be a hydrogenated terpene-based resin, ahydrogenated ester-based resin, or a hydrogenateddicyclopentadiene-based resin. The tackifier may have a weight averagemolecular weight of approximately 200 to 5,000. A content of thetackifier may be suitably controlled as needed. For example, the contentof the tackifier may be selected in consideration of the gel content andmicro gel content described above. According to one example, thetackifier may be included at 5 to 100 parts by weight relative to 100parts by weight of a solid content of the pressure-sensitive adhesivecomposition.

The pressure-sensitive adhesive composition may further include amoisture absorbent when needed. The term “moisture absorbent” may referto a material that can remove moisture or vapor penetrated into apressure-sensitive adhesive film to be described below through achemical reaction. When the pressure-sensitive adhesive composition ofthe present invention includes a moisture absorbent, a lighttransmittance to be described below may not be satisfied in theformation in a film, but instead, excellent moisture barrier ability maybe realized. Specifically, the pressure-sensitive adhesive compositionmay be formed in a film to be applied to encapsulation of an organicelectronic device. In this case, when the pressure-sensitive adhesivecomposition does not include a moisture absorbent and exhibits excellenttransparency, it may be applied to encapsulation of a top-emissiveorganic electronic device, or when the pressure-sensitive adhesivecomposition includes a moisture absorbent and exhibits excellentmoisture barrier ability, it may be applied to encapsulation of abottom-emissive organic electronic device. However, the presentinvention is not limited thereto. That is, when the pressure-sensitiveadhesive composition does not include a moisture absorbent and exhibitsexcellent transparency, it may be applied to encapsulation of abottom-emissive organic electronic device.

For example, the moisture absorbent may be present while being uniformlydispersed in the pressure-sensitive adhesive composition or apressure-sensitive adhesive layer to be described below. Here, theuniformly dispersed state may mean a state in which the moistureabsorbent is present even in any part of the pressure-sensitive adhesivecomposition or the pressure-sensitive adhesive layer at the same orsubstantially the same density. As the moisture absorbent used herein,for example, a metal oxide, a sulfate, or an organic metal oxide may beused. Specifically, the sulfate may be magnesium sulfate, sodiumsulfate, or nickel sulfate, and the organic metal oxide may be aluminumoxide octylate. Here, the metal oxide may be phosphorus pentoxide(P₂O₅), lithium oxide (Li₂O), sodium oxide (Na₂O), barium oxide (BaO),calcium oxide (CaO), or magnesium oxide (MgO), and the metal salt may bea sulfate such as lithium sulfate (Li₂SO₄), sodium sulfate (Na₂SO₄),calcium sulfate (CaSO₄), magnesium sulfate (MgSO₄), cobalt sulfate(CoSO₄), gallium sulfate (Ga₂(SO₄)₃), titanium sulfate (Ti(SO₄)₂), ornickel sulfate (NiSO₄); a metal halide such as calcium chloride (CaCl₂),magnesium chloride (MgCl₂), strontium chloride (SrCl₂), yttrium chloride(YCl₃), copper chloride (CuCl₂), cesium fluoride (CsF), tantalumfluoride (TaF₅), niobium fluoride (NbF₅), lithium bromide (LiBr),calcium bromide (CaBr₂), cesium bromide (CeBr₃), selenium bromide(SeBr₄), vanadium bromide (VBr₃), magnesium bromide (MgBr₂), bariumiodide (BaI₂), or magnesium iodide (MgI₂); or a metal chlorate such asbarium perchlorate (Ba(ClO₄)₂) or magnesium perchlorate (Mg(ClO₄)₂), butthe present invention is not limited thereto. As the moisture absorbentthat can be included in the pressure-sensitive adhesive composition, oneor at least two of the above-described materials may be used. In oneexample, when at least two of the above materials are used, the moistureabsorbent may be calcined dolomite.

Such a moisture absorbent may be controlled in a suitable size accordingto its use. In one example, an average diameter of the moistureabsorbent may be controlled to approximately 10 to 15000 nm. A moistureabsorbent having the above range of the average diameter may be easilystored due to a not too high reaction speed with moisture, and mayeffectively remove moisture without damage to an element to beencapsulated.

A content of the moisture absorbent may be suitably selected withoutparticular limitation in consideration of a desired barriercharacteristic.

The pressure-sensitive adhesive composition may further include amoisture blocker when needed. The term “moisture blocker” used hereinmay refer to a material that can block or prevent migration of moistureor vapor in a film while having no or low reactivity with moisture. Asthe moisture blocker, one or at least two of clay, talc, pin-typesilica, planar silica, porous silica, zeolite, titania, and zirconia maybe used. In addition, a surface of the water blocker may be treated withan organic modifier to facilitate penetration of an organic material. Assuch an organic modifier, for example, dimethyl benzyl hydrogenatedtallow quaternary ammonium, dimethyl hydrogenated tallow quaternaryammonium, methyl tallow bis-2-hydroxyethyl quaternary ammonium, dimethylhydrogenated tallow 2-ethylhexyl quaternary ammonium, dimethyldehydrogenated tallow quaternary ammonium, or a mixture thereof may beused.

A content of the moisture blocker may be suitably selected withoutparticular limitation in consideration of a desired blockingcharacteristic.

In addition to the above-described components, various additives may beincluded in the pressure-sensitive adhesive composition according to itsuse and a process of manufacturing a pressure-sensitive adhesive filmthat will be described below. For example, the pressure-sensitiveadhesive composition may include a curable material, a crosslinkingagent, or a filler at a suitable range of content according to a desiredphysical property.

In another aspect, the present invention provides a pressure-sensitiveadhesive film. In addition, the pressure-sensitive adhesive film mayinclude a pressure-sensitive adhesive layer formed of theabove-described pressure-sensitive adhesive composition or a crosslinkedproduct thereof. The pressure-sensitive adhesive layer may also beformed in a film or sheet. Such a pressure-sensitive adhesive layer maybe used to encapsulate an organic electronic element.

In an exemplary embodiment of the present invention, thepressure-sensitive adhesive layer may be formed in a monolayer structureas described above, or may be formed of at least two layers that will bedescribed below. For example, the pressure-sensitive adhesive layer mayinclude a first layer containing the above-described pressure-sensitiveadhesive composition or a crosslinked product thereof and a second layerincluding a pressure-sensitive adhesive resin or an adhesive resin. Thepressure-sensitive adhesive resin or adhesive resin included in thesecond layer may be the same as or different from the above-describedencapsulating resin, and may be suitably selected by a conventionaltechnician according to a purpose. In addition, the first and secondlayers may or may not include a moisture absorbent.

In one example, the pressure-sensitive adhesive resin included in thesecond layer may include a curable resin including at least oneheat-curable functional group such as a glycidyl group, an isocyanategroup, a hydroxyl group, a carboxyl group, or an amide group, or atleast one electromagnetic wave-curable functional group such as anepoxide group, a cyclic ether group, a sulfide group, an acetal group,or a lactone group, which may be cured to exhibit an adhesivecharacteristic. In addition, a specific type of such a resin may be, butis not limited to, an acryl resin, a polyester resin, an isocyanateresin, or an epoxy resin.

In the present invention, as the curable resin, an aromatic oraliphatic, or linear or branched epoxy resin may be used. In oneexemplary embodiment of the present invention, an epoxy resin containingat least two functional groups and having an epoxy equivalent of 180 to1,000 g/eq may be used. When the epoxy resin having the above range ofepoxy equivalent is used, characteristics of the cured product such asadhesive performance and a glass transition temperature may beeffectively maintained. Such an epoxy resin may be one or a mixture ofat least two of a cresol novolac epoxy resin, a bisphenol A-type epoxyresin, a bisphenol A-type novolac epoxy resin, a phenol novolac epoxyresin, a tetrafunctional epoxy resin, a biphenyl-type epoxy resin, atriphenol methane-type epoxy resin, an alkyl-modified triphenol methaneepoxy resin, a naphthalene-type epoxy resin, a dicyclopentadiene-typeepoxy resin, and a dicyclopentadiene modified phenol-type epoxy resin.

In an exemplary embodiment of the present invention, the second layermay include another component such as an active energy ray-polymerizablecompound, a radical initiator, a tackifier, a moisture absorbent, amoisture blocker, a dispersing agent, or a silane compound, which may bethe same as or different from that of the first layer, in addition tothe above-described resin. In addition, the second layer may include acurable material, a curing agent, or a filler at a suitable range ofcontent according to a desired physical property.

A sequence of laminating the first and second layers is not particularlylimited, and thus the second layer may be formed on the first layer, orthe first layer may be formed on the second layer.

In one example, the pressure-sensitive adhesive film may include abarrier film on one surface of the pressure-sensitive adhesive layer.The bather film may be formed of any material generally used in the artwithout limitation. For example, here, the barrier film may include abase layer, an organic undercoating layer, an inorganic depositionlayer, and an organic top-coating layer, and the organic top-coatinglayer may be in contact with the pressure-sensitive adhesive layer.

The pressure-sensitive adhesive film may have a water vapor transmissionrate (WVTR) measured with respect to a thickness direction of the filmwhile being formed in a film having a thickness of 10 μm of 50, 40, 30,20, or 10 g/m²·day or less at 100° F. and a relative humidity of 100%.By controlling a composition or crosslinking condition of apressure-sensitive adhesive layer including a pressure-sensitiveadhesive composition to have such a WVTR, an encapsulation orcapsulation structure which can stably protect an element by effectivelyblocking moisture or oxygen penetrated from an external environment whenbeing applied to an encapsulation or capsulation structure of anelectronic device may be realized. The lower WVTR, the better moisturebarrier ability, and therefore the lower limit of the WVTR may be, butis not particularly limited to, 0 g/m²·day.

In addition, the pressure-sensitive adhesive film may have an excellentlight transmittance with respect to a visible-ray region. In oneexample, the pressure-sensitive adhesive film of the present inventionmay have a light transmittance of 85% or more with respect to thevisible-ray region. For example, the pressure-sensitive adhesive filmmay have a light transmittance of 85%, 87%, or 90% or more with respectto the visible-ray region. In addition, the pressure-sensitive adhesivefilm of the present invention may have a low haze with the excellentlight transmittance. In one example, the pressure-sensitive adhesivefilm may have a haze of 3%, 2%, 1%, 0.8%, 0.5%, or 0.3% or less. Thatis, the pressure-sensitive adhesive film according to the presentinvention may realize excellent optical characteristics as well asreliability at high temperature and high humidity by satisfying the gelcontent and micro gel content according to Equations 1 and 2 asdescribed above.

The pressure-sensitive adhesive film may further include a base film orrelease film (hereinafter, can be referred to as a “first film”), andthe pressure-sensitive adhesive layer may be formed on the base orrelease film. The structure may further include a base or release filmformed on the pressure-sensitive adhesive layer (hereinafter, can bereferred to as a “second film”).

FIGS. 1 and 2 are cross-sectional views of exemplary pressure-sensitiveadhesive films.

A pressure-sensitive adhesive film 1, as shown in FIG. 1, may include apressure-sensitive adhesive layer 11 formed on a base or release film12. Another exemplary pressure-sensitive adhesive film 2, as shown inFIG. 2, may further include a base or release film 21 formed on apressure-sensitive adhesive layer 11. Although not shown in FIGS. 1 and2, the pressure-sensitive adhesive film may also have thepressure-sensitive adhesive composition without a supporting base suchas a base or release film, and therefore have a structure only includinga pressure-sensitive adhesive layer formed in a film or sheetmaintaining a solid phase or a semi-solid phase at room temperature, ora structure in which a pressure-sensitive adhesive layer is formed onboth surfaces of one base or release film.

A specific type of the first film is not particularly limited. As thefirst film, for example, a plastic film may be used. The first film maybe a polyethyleneterephthalate film, a polytetrafluoroethylene film, apolyethylene film, a polypropylene film, a polybutene film, apolybutadiene film, a vinyl chloride copolymer film, a polyurethanefilm, an ethylene-vinyl acetate film, an ethylene-propylene copolymerfilm, an ethylene-ethyl acrylate copolymer film, an ethylene-methylacrylate copolymer film, or a polyimide film.

When the first film is a release film, suitable release treatment may beperformed on one or both surfaces of such a plastic film. As a releasingagent used for release treatment, an alkyd-based releasing agent, asilicon-based releasing agent, a fluorine-based releasing agent, anunsaturated ester-based releasing agent, a polyolefin-based releasingagent, or a wax-based releasing agent may be used. In consideration ofheat resistance, an alkyd-based releasing agent, a silicon-basedreleasing agent, or a fluorine-based releasing agent among the aboveexamples is conventionally used, but the present invention is notlimited thereto.

As the first film, for example, a plastic film in which a gas barrierlayer is formed on a top or side surface of a base may be used. Such afilm may directly constitute, for example, a substrate of an organicelectronic device to be used for realizing a flexible element.

A type of the second film is not particularly limited, either. Forexample, as the second film, within the category of the first filmlisted above, one that is the same as or different from the first filmmay be used.

A thickness of the first or second film is not particularly limited. Inone example, the thickness of the first film may be approximately 50 to500 or 100 to 200 μm. In such a range, a process of preparing ormanufacturing a pressure-sensitive adhesive or an organic electronicdevice may be effectively automated, and advantageous effects ineconomic feasibility may be achieved.

The thickness of the second film is not particularly limited, either.For example, the thickness of the second film may be the same as, orrelatively smaller or larger than that of the first film.

The pressure-sensitive adhesive layer of the pressure-sensitive adhesivefilm includes the pressure-sensitive adhesive composition, and is formedin a film or sheet. In the pressure-sensitive adhesive layer, thepressure-sensitive adhesive composition may be in a crosslinked ornon-crosslinked state. The pressure-sensitive adhesive layer may be in asolid or semi-solid phase at room temperature. A curablepressure-sensitive adhesive resin included in the pressure-sensitiveadhesive layer in a sold or semi-sold phase may be in a non-crosslinkedstate. Such a pressure-sensitive adhesive resin may form a crosslinkingstructure in an encapsulation structure of an organic electronicelement, which will be described below.

A thickness of the pressure-sensitive adhesive layer is not particularlylimited, and in consideration of its uses, may be suitably selected. Forexample, the pressure-sensitive adhesive layer may have a thickness ofapproximately 5 to 200 μm. The thickness of the pressure-sensitiveadhesive layer may be controlled in consideration of, for example,embeddability when being used as an encapsulant of an organic electronicelement and processability or economic feasibility.

In still another aspect, the present invention provides a method ofmanufacturing a pressure-sensitive adhesive film. The exemplarypressure-sensitive adhesive film may be manufactured by plasticizing thepressure-sensitive adhesive composition in a film or sheet.

In one example, the method may include applying a coating solutionincluding the pressure-sensitive adhesive composition on a base orrelease film in a sheet or film, and drying the applied coatingsolution. The method may further include adhering an additional base orrelease film to the dried coating solution.

The coating solution including the pressure-sensitive adhesivecomposition may be prepared by, for example, dissolving or dispersingcomponents of each pressure-sensitive adhesive composition describedabove in a suitable solvent. In one example, the pressure-sensitiveadhesive composition may be prepared by dissolving or dispersing themoisture absorbent, blocker, or filler in a solvent when needed,grinding the resulting product, and mixing the ground moistureabsorbent, blocker, or filler with an encapsulating resin.

A type of a solvent used in preparation of the coating solution is notparticularly limited. However, when time to dry the solvent is too long,or it is necessary to dry the solvent at a high temperature, there mayhave some problems in workability or durability of a pressure-sensitiveadhesive film. For this reason, a solvent having a volatile temperatureof 150° C. or less may be used. In consideration of film moldability, asmall amount of the solvent having the above range of the volatiletemperature may be used. The solvent may be, but is not limited to, oneor at least two of methylethylketone (MEK), acetone, toluene, dimethylformamide (DMF), methyl cellosolve (MCS), tetrahydrofuran (THF), xylene,and N-methylpyrrolidone (NMP).

A method of applying the coating solution to the base or release filmmay be, but is not particularly limited to, a known coating method suchas knife coating, roll coating, spray coating, gravure coating, curtaincoating, comma coating, or lip coating.

The applied coating solution may be dried to volatilize the solvent,thereby forming a pressure-sensitive adhesive layer. The drying may beperformed, for example, at 70 to 150° C. for 1 to 10 minutes. The dryingcondition may be changed in consideration of a type of the used solvent.

After drying, an additional base or release film may be formed on thepressure-sensitive adhesive layer.

In yet another aspect, the present invention provides a product forencapsulating an organic electronic device. The product forencapsulating an organic electronic device may include a substrate; anorganic electronic element formed on the substrate; and apressure-sensitive adhesive film encapsulating an entire surface, forexample, both top and side surfaces of the organic electronic element.The pressure-sensitive adhesive film may include a pressure-sensitiveadhesive layer containing a pressure-sensitive adhesive composition in acrosslinked state. The product for encapsulating an organic electronicdevice may further include a cover substrate formed on a top surface ofthe pressure-sensitive adhesive layer.

Here, the organic electronic element may be, for example, an organiclight emitting element, and in one example, may be a top-emissiveorganic light emitting element.

In yet another aspect, the present invention provides a method ofmanufacturing an organic electronic device. The product forencapsulating an organic electronic device may be manufactured using,for example, the pressure-sensitive adhesive film.

The pressure-sensitive adhesive layer may be formed as an encapsulatinglayer for effectively fixing and supporting the substrate and a coversubstrate, while exhibiting excellent moisture barrier property andoptical property.

In addition, the pressure-sensitive adhesive layer may exhibit excellenttransparency, and may be stable regardless of a type of the organicelectronic device, for example, a top-emissive or bottom-emissiveorganic electronic device.

The term “encapsulating layer” used herein may refer to apressure-sensitive adhesive layer covering both top and side surfaces ofthe organic electronic element.

FIG. 3 is a schematic diagram of an exemplary organic electronic devicein which an organic electronic element is an organic light emittingelement.

To manufacture the organic electronic device, for example, applying theabove-described pressure-sensitive adhesive film to the substrate onwhich the organic electronic element is formed in order to cover theorganic electronic element; and curing the pressure-sensitive adhesivefilm may be included.

The term “curing” used herein may refer to preparing apressure-sensitive adhesive by forming the pressure-sensitive adhesivecomposition of the present invention to have a crosslinking structurethrough heating or UV irradiation.

Particularly, an organic electronic element 32 may be formed by forminga transparent electrode on a glass or polymer film 31 used as asubstrate by a method such as vacuum deposition or sputtering, forminglayers of emissive organic materials, composed of, for example, a holetransport layer, an emitting layer, and an electron transport layer onthe transparent electrode, and further forming an electrode layerthereon. Subsequently, a pressure-sensitive adhesive layer of thepressure-sensitive adhesive film is disposed to cover an entire surfaceof the organic electronic element 32 of the substrate 31 which has gonethrough the above-described process.

Subsequently, an encapsulating layer may be formed by compressing thepressure-sensitive adhesive layer on the organic electronic elementusing a laminator while being heated to provide mobility, andcrosslinking a resin in the pressure-sensitive adhesive layer.

In one example, the pressure-sensitive adhesive layer 33 disposed tocover an entire surface of the organic electronic element 32 may bepreviously transferred to a cover substrate 34 such as a glass or apolymer film. The transfer of the pressure-sensitive adhesive layer tothe cover substrate 34 may be performed using a vacuum press or vacuumlaminator while being heated after a first or second film is peeled offfrom the pressure-sensitive adhesive film and the pressure-sensitiveadhesive layer is in contact with the cover substrate 34. When apressure-sensitive adhesive includes a heat-curable pressure-sensitiveadhesive resin and a curing reaction is excessively performed during theprocess, a cohesive strength or pressure-sensitive adhesive strength ofthe encapsulating layer is probably reduced. Therefore, a processtemperature may be controlled to approximately 100° C. or less, and aprocess time may be controlled within 5 minutes.

An encapsulating layer may be formed by disposing the cover substrate 34to which the pressure-sensitive adhesive layer is transferred on theorganic electronic element 32, and performing the heat compressionprocess.

An encapsulating layer may be formed by curing the pressure-sensitiveadhesive layer 33. The curing process may be performed in a suitableheating chamber or UV chamber, for example, according to a method ofcuring a curable pressure-sensitive adhesive resin. A heating conditionor a condition of irradiating an active energy ray may be suitablyselected in consideration of stability of the organic electronic elementand curability of the pressure-sensitive adhesive resin, and to increasecompression efficiency, autoclaving may also be performed withapplication of heat and pressure at the same time.

Here, one example of the method of manufacturing an organic electronicdevice is described, but the organic electronic device may bemanufactured by a different method. For example, the manufacture of thedevice is performed by the above-described method, but a sequence orcondition of the process may be changed. For example, the encapsulatinglayer may be formed by previously transferring the pressure-sensitiveadhesive layer to the substrate 31, not to the cover substrate 34, andperforming a curing process while the cover substrate 34 is laminated.

Effects

The present invention can provide a pressure-sensitive adhesivecomposition that can effectively block moisture or oxygen penetratedinto an organic electronic device from an external environment, andexhibit reliability under harsh conditions such as high temperature andhigh humidity and excellent optical characteristics, and apressure-sensitive adhesive film including the same.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are cross-sectional views of pressure-sensitive adhesivefilms according to exemplary embodiments of the present invention;

FIG. 3 is a cross-sectional view of a product for encapsulating anorganic electronic device according to an exemplary embodiment of thepresent invention;

FIG. 4 is a diagram showing results of a reliability test of apressure-sensitive adhesive film according to Example 1 of the presentinvention; and

FIG. 5 is a diagram showing results of a reliability test of apressure-sensitive adhesive film according to Comparative Example 1 ofthe present invention.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1, 2: pressure-sensitive adhesive film    -   11: pressure-sensitive adhesive layer    -   12: first film    -   21: second film    -   3: organic electronic device    -   31: substrate    -   32: organic electronic element    -   33: pressure-sensitive adhesive layer or encapsulating layer    -   34: cover substrate

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, the present invention will be described in detail withreference to Examples and Comparative Examples, but the scope of thepresent invention is not limited to the following Examples.

Example 1

A coating solution was prepared by adding 90 g of a butyl rubber(LANXESS, BUTYL 301) as an encapsulating resin, 10 g of a hydrogenatedDCPD-based tackifier resin (SU-90, Kolon) as a tackifier, 15 g oftricyclodecane dimethanol diacrylate (M262, Miwon) as an active energyray-polymerizable compound, and 1 g of2,2-dimethoxy-1,2-diphenylethane-1-one (Irgacure651, Ciba) as a radicalinitiator, and diluting the mixture in toluene to have a solid contentof approximately 15 wt %.

The prepared solution was coated on a released surface of release PET,and dried in an oven at 100° C. for 15 minutes, thereby manufacturing apressure-sensitive adhesive film including a pressure-sensitive adhesivelayer having a thickness of 20 μm. Physical properties of the samplewere measured after a UV ray was irradiated at 2 J/cm² on themanufactured film.

Example 2

A pressure-sensitive adhesive film was manufactured by the same methodas described in Example 1, except that 60 g of a butyl rubber (LANXESS,BUTYL 301) and 30 g of polyisobutylene (including 25 g of BASF, B80, and5 g of B15) were used as encapsulating resins.

Example 3

A pressure-sensitive adhesive film was manufactured by the same methodas described in Example 1, except that CaO (Aldrich) was added as amoisture absorbent at 20 parts by weight relative to 100 parts by weightof a butyl rubber and a tackifier resin.

Comparative Example 1

A pressure-sensitive adhesive film was manufactured by the same methodas described in Example 1, except that 80 g of polyisobutylene (BASF,B80) was used as an encapsulating resin, 2-hydroxyethyl acrylate (HEA,Aldrich) was added, and isophorone diisocyanate (IPDI, Aldrich) wasadded.

Comparative Example 2

A pressure-sensitive adhesive film was manufactured by the same methodas described in Example 1, except that polybutadiene dimethacrylate(CN301, Sartomer) was used as an active energy ray-polymerizablecompound.

Comparative Example 3

A pressure-sensitive adhesive film was manufactured by the same methodas described in Example 1, except that a content of an active energyray-polymerizable compound was changed to 3 g.

Comparative Example 4

A pressure-sensitive adhesive film was manufactured by the same methodas described in Example 1, except that a content of an active energyray-polymerizable compound was changed to 0 g.

Comparative Example 5

A coating solution (pressure-sensitive adhesive composition) wasprepared by mixing 99 parts by weight of n-butyl acrylate and 1 part byweight of 2-hydroxyethyl methacrylate, and blending a multifunctionalepoxy compound (trimethylolpropane triglycidylether), a cationicphotoinitiator (triarylsulfonium hexafluoroantimonate), andγ-glycidoxypropyl trimethoxy silane in an acryl pressure-sensitiveadhesive having a molecular weight (Mw) of approximately 1,800,000, anddiluting the mixture at a suitable concentration. A pressure-sensitiveadhesive layer was formed to have a thickness of approximately 50 μm bycoating and drying the prepared coating solution on a release-treatedsurface of a polyethyleneterephthalate (PET) film on which releasetreatment was performed, and forming a crosslinking structure byirradiating a UV ray.

Comparative Example 6

A pressure-sensitive adhesive film was manufactured by the same methodas described in Example 1, except that 80 g of polyisobutylene (BASF,B80) was used as an encapsulating resin instead of a butyl rubber, and15 g of fumed silica (R812, Evonik) was added.

Hereinafter, physical properties were evaluated by the following methodsin the Examples and Comparative Examples.

1. Gel ContentGel content (wt %)=B/A×100

Here, A is a weight of the pressure-sensitive adhesive composition, andB is a dry weight of an insoluble content of the pressure-sensitiveadhesive composition remaining after the pressure-sensitive adhesivecomposition was dipped in toluene at 60° C. for 24 hours and filteredthrough a 200-mesh sieve (pore size: 200 μm). In Comparative Example 5,ethyl acetate was used instead of toluene.

2. Micro Gel ContentMicro gel content (wt %)=C/A×100

Here, A is a weight of the pressure-sensitive adhesive composition, andC is a dry weight of the pressure-sensitive adhesive compositionremaining after the pressure-sensitive adhesive composition was dippedin toluene at 60° C. for 24 hours, primarily filtered through a 200-meshsieve (pore size: 200 μm), and secondarily filtered through a 1000-meshsieve (pore size: 5 μm). In Comparative Example 5, ethyl acetate wasused instead of toluene.

In addition, the micro gel could be detected using a 5 μm syringe. Forexample, when the pressure-sensitive adhesive composition was primarilyfiltered through a 200-mesh sieve (pore size: 200 μm) and passed througha 5 μm syringe, the pressure-sensitive adhesive composition having amicro gel content of more than 3% represented by Equation 2 did not passsince a syringe was clogged due to a micro gel (having a size ofapproximately 100 nm to 20 μm) present in the composition. When thecomposition was not filtered, it was represented as X in Table 1. On theother hand, when there was almost no or no micro gel, the compositionpassed through the syringe (represented as O in Table 1), and the microgel content represented in Equation 2 was detected at 3% or less. Inaddition, through morphological analysis, the presence of the micro gelcould be actually confirmed.

3. Water Vapor Transmission Rate (WVTR)

A resin composition was prepared by dissolving the resin used in

Example or Comparative Example in a solvent. The resin composition wasapplied to a base film having a thickness of 38 μm (release polyesterfilm, RS-21G, SKC). Subsequently, the composition was dried at 110° C.for 10 minutes, thereby forming a film-type layer having a thickness of100 μm. Afterward, the base film was peeled, and then a WVTR of thefilm-type layer was measured in a thickness direction, while the layerwas maintained at 100° F. and a relative humidity of 100%. The WVTR wasmeasured according to a specification of ASTM F1249.

4. Evaluation of Reliability

(1) A sample was prepared by laminating the film manufactured in Exampleor Comparative Example on a barrier film (serving as a cover substrate),laminating the resulting product between glass substrates, and pressureand heat-compressing the resulting product using an autoclave at 50° C.and 5 atm. Afterward, the sample was maintained in a constanttemperature and constant humidity chamber at 85° C. and a relativehumidity of 85% for approximately 500 hours, and observed whetherlifting, bubbles, or hazes were generated at an interface between aglass substrate and a pressure-sensitive adhesive layer. When beingviewed with the naked eye, at the interface between the glass substrateand the pressure-sensitive adhesive layer, if at least one lifting,bubble, or haze was generated, it was represented as X, and if nolifting, bubble, or haze was generated, it was represented as O.

(2) A sample was manufactured by the same method, except that apolarizing plate was further laminated on a barrier film in a method ofevaluating reliability at 85° C. and a relative humidity of 85%, andobserved to check whether lifting or bubbles were generated at aninterface between a glass substrate and a pressure-sensitive adhesivelayer while being maintained in a 80° C. chamber for approximately 500hours. When being viewed with a naked eye, if there was at least onelifting or bubble at the interface between the glass substrate and thepressure-sensitive adhesive layer, it was represented as X, and if therewas no lifting or bubble, it was represented as O.

5. Measurement of Light Transmittance and Haze

A light transmittance of the pressure-sensitive adhesive filmmanufactured as described above was measured at 550 nm using a UV-Visspectrometer, and a haze of the pressure-sensitive adhesive film wasmeasured using a haze meter according to a standard test method of JISK7105.

TABLE 1 High temperature High temperature Micro gel & high humidityreliability ◯/X reliability 80° C., Light Gel (5 μm WVTR 85° C.Polarizing transmittance Haze % % syringe) g/m² · day 85% RH plate % —Example 1 74 0 ◯ 4 ◯ ◯ 90 0.2 Example 2 51 0 ◯ 4 ◯ ◯ 90 0.2 Example 3 850 ◯ 6 ◯ ◯ — — Comparative 55 4.1 X 4 ◯ X 90 2.7 Example 1 Comparative 00 ◯ 5 X X 90 0.3 Example 2 Comparative 43 0 ◯ 4 ◯ X 90 0.2 Example 3Comparative 0 0 ◯ 4 X X 90 0.1 Example 4 Comparative 83 0 ◯ >500 ◯ ◯ 900.2 Example 5 Comparative 0 0 ◯ 4 ◯ X 89 1.6 Example 6

What is claimed is:
 1. A pressure-sensitive adhesive compositioncomprising an encapsulating resin comprising a copolymer of a diene andan olefin-based compound haying one carbon-carbon double bond, atackifier and an active energy rav-polymerizable compound included at 5to 18 parts by weight relative to 100 parts by weight of theencapsulating resin, wherein the active energy ray-polymerizablecompound satisfies Formula 1:

where R₁ is hydrogen or an alkyl group having 1 to 4 carbon atoms, n isan integer of 2 or more, and X is a residue inducted from a linear,branched, or cyclic alkyl group having 3 to 30 carbon atoms, wherein thepressure sensitive adhesvie composition has a gel content represented byEquation 1 of 50% or more, a micro gel content represented by Equation 2of 3% or less, and a water vapor transmission rate in a thicknessdirection while being formed in a film having a thickness of 100 μm of50 g/m², day or less:Gel content (wt %)=B/A×100   [Equation 1]Micro gel content (wt %)=C/A×100   [Equation 2] wherein in Equations 1and 2, A is a mass of the pressure-sensitive adhesive composition, inEquation 1, B is a dry mass of an insoluble content of thepressure-sensitive adhesive composition remaining after being dipped intoluene at 60° C. for 24 hours and filtered through a 200-mesh sieve(pore size of 200 μm), and in Equation 2, C is a dry mass of aninsoluble content of the pressure-sensitive adhesive compositionremaining after being dipped in toluene at 60° C. for 24 hours,primarily filtered through a 200-mesh sieve (pore size: 200 μm), andsecondarily filtered through a 1000-mesh sieve (pore size: 5 μm).
 2. Thecomposition according to claim 1, which has a gel content represented byEquation 1 of 50 to 99%.
 3. The composition according to claim 1, whichhas a light transmittance of 85% or more with respect to a visible-rayregion while being formed in a film.
 4. The composition according toclaim 1, which has a haze of 3% or less while being formed in a film. 5.The composition according to claim 1, further comprising: a radicalinitiator.
 6. The composition according to claim. 1, further comprising:a moisture absorbent.
 7. A pressure-sensitive adhesive film, comprisinga pressure-sensitive adhesive layer, wherein the pressure-sensitiveadhesive layer comprises the pressure-sensitive adhesive composition ofclaim 1 or a crosslinked product thereof.
 8. The pressure-sensitiveadhesive film according to claim 7, wherein the film comprises a firstlayer having the pressure-sensitive adhesive layer and a second layerhaving a pressure-sensitive adhesive resin or an adhesive resin.
 9. Thepressure-sensitive adhesive film according to claim 7, which has a lighttransmittance of 85% or more with respect to a visible-ray region. 10.The pressure-sensitive adhesive film according to claim 7, which has ahaze of 3% or less.
 11. An organic electronic device, comprising: asubstrate; an organic electronic element formed on the substrate; andthe pressure-sensitive adhesive film according to claim 7 encapsulatethe organic electronic element.
 12. A method of manufacturing an organicelectronic device, comprising: applying the pressure-sensitive adhesivefilm of claim 7 to a substrate on which an organic electronic element isformed in order to cover the organic electronic element; and curing thepressure-sensitive adhesive film.